Lyle McDonald

In 2018 I released The Women’s Book: Vol 1, a comprehensive guide to women’s nutrition, muscle gain and fat loss. At 425 pages, containing over 600 scientific references, it represents the most comprehensive book ever written on the topic (available in its full form here). Since a book of that size can be overwhelming, I decided to divide it into smaller sections of grouped information to make it a bit easier to digest the information before tackling the next section.

This is section 3 of that book which includes Chapter 8-11.

In 2018 I released The Women’s Book: Vol 1, a comprehensive guide to women’s nutrition, muscle gain and fat loss. This is section 3 of that book which includes Chapter 8-11 on energy balance, metabolic adaptation, and a detailed look across two chapters on women’s issues with fat loss and fat gain.

In Chapter 8, I address the issue of energy balance which refers to the relationship between energy intake and energy expenditure. Energy intake refers to the calories that come into the body via food and the four macronutrients: protein, carbohydrate, fat and alcohol. Energy expenditure refers to all of the calories that are burned during the day and there are four contributors to this: Resting Metabolic Rate (RMR, calories burned at rest), the Thermic Effect of Food (TEF, calories burned from the metabolism of foods)), the Thermic Effect of Activity (TEA, calories burned during formal exercise) and Non-Exercise Activity Thermogenesis (NEAT, calories burned during activity that is not exercise).

The chapter continues by looking at the energy composition of different fuels in the body along with the old “rule” that 3,500 calories equals one pound. I finish by returning to the topic of body composition and what is being gained or lost during weight gain or loss as this explains why the “rule” is so often wrong. As a lead-in to Chapter 9, I address the often ignored fact that the energy balance equation changes.

Continuing from the idea that the energy balance equation can change, Chapter 9 addresses the issue of metabolic adaptation, all of the changes that can and do occur in energy intake and energy expenditure in response to either fat loss or weight gain. The primary topic of the chapter are the adaptations that occur in response to fat loss, looking at the overall change in total daily energy expenditure or TDEE. In response to fat loss, all four components change (going down) due to both the decrease in bodyweight/bodyfat along with an adaptive component.

I look at these in detail along with other metabolic adaptations that occur as a response to fat loss. The chapter also looks at the adaptations that occur in response to weight gain, individual differences and the idea that Yo-Yo dieting (repeated cycles of weight gain and loss) can permanently affect metabolism. Finally I look at some of the hormonal drivers on the adaptations.

Chapter 11 begins a discussion of the specific issues that women have in terms of fat agin and fat loss. First it addresses the differences in body composition between women and men along with the impact of the different hormonal modifiers (PCOS, birth control, general obesity and aging/menopause) before looking at statistics on the rate of obesity in women compared to men. The chapter than gets into a detailed discussion of gender differences in terms of both energy intake (via appetite and food preferences) and energy expenditure before examining different in nutrient metabolism both during and after a meal. Finally the chapter addresses the differences in how women and men lose weight along with the issue of how fat patterning can change in women with fat loss and fat regain.

Following from Chapter 10, Chapter 11 looks in detail at direct research on weight and fat loss between women and men. This includes data on diet alone, diet with exercise and exercise alone in terms of how they do or do not impact on weight and fat loss. As there are often significant differences for women carrying different amounts of body fat, those differences are also examined.

Finally I address the issue of gender differences in how the body regulates energy balance (called homeostasis) along with the evolutionary reasons that the sexes differ in this regard. In short, women’s bodies tend to conserve energy more effectively than men but this was an important adaptation due to the critical importance of women for the survival of the human race.

The references section includes the scientific and other literature that the previous chapter draws on for those who may wish to delve more deeply.

50 cents from every purchase from will be donated to The Women’s Sports Foundation, a 501c3 charity founded by Billie Jean King and dedicated to creating leaders by ensuring all girls access to sports.